Mower with improved exhaust gas component cooling

ABSTRACT

A mower includes: a driver&#39;s seat provided to a vehicle frame. A transmission is arranged at least partially below the driver&#39;s seat. An engine arranged rearward of the transmission such that a bottom end of the engine is positioned higher than a bottom end of the transmission. An exhaust gas purification device is arranged rearward of the engine. An air cleaner is arranged forward of the exhaust gas purification device and above the engine. A radiator extends from an area between the transmission and the engine so as to project further upward than the air cleaner through an area between the driver&#39;s seat and the air cleaner.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of JapaneseApplication No. 2015-000359, filed on Jan. 5, 2015, the disclosure ofwhich is expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mower having a mower unit mounted ona vehicle frame and a diesel engine installed to the rear of a driver'sseat. The vehicle frame is suspended on front wheels on a front side andsuspended on rear wheels on a rear side. The mower uses a system forimproving a cooling of exhaust gas components.

2. Description of Related Art

In order to improve and resolve the environmental concerns of recentyears, exhaust gas regulations have been toughened for diesel enginesand the like. In work vehicles such as construction or agriculturalmachinery, various technologies have been developed which reduceparticulate matter contained in exhaust gas so as to comply with suchexhaust gas regulations. For example, instead of a conventional muffler,an exhaust gas purification device collecting particulate mattercontained in exhaust gas may be mounted to a work vehicle. The exhaustgas purification device passes the exhaust gas through a dieselparticulate filter (hereafter referred to simply as DPF) installedtherein to collect the particulate matter. The collected particulatematter accumulates gradually in the DPF of the exhaust gas purificationdevice, and so in order to prevent the DPF from clogging and prevent anincrease in air resistance of the exhaust system, the particulate mattermust be burned off and the DPF renewed. Therefore, an outer surface ofthe exhaust gas purification device housing the DPF must be configuredto avoid being excessively cooled, and an exhaust pipe must beeffectively cooled so as to reduce a temperature of the exhaust gasdischarged to the exterior from the exhaust gas purification device. Inorder to accomplish this, a large air inflow space must be preservedforward of a radiator, which acts as an external air intake opening toan engine compartment, in order to circulate a sufficient amount ofcooling air to the engine compartment where the diesel engine isarranged.

A work vehicle disclosed in Japanese Patent Laid-open Publication No.2012-026326 is configured as a riding mower having a mower unit arrangedbelow a vehicle frame between left-right pairs of front and rear wheels,a driver's seat arranged at a center portion of the vehicle frame, anengine compartment covered by a hood formed at a rear portion of thevehicle frame, and an engine and engine components arranged within theengine compartment. The engine is a diesel engine having a radiator anda cooling fan provided on a front side. A DPF (exhaust gas purificationdevice) purifying engine exhaust gas is arranged at a position rearwardand above the diesel engine, and an air cleaner is provided at aposition above the diesel engine. The exhaust gas flowing in from a leftfront side of the DPF is discharged through a short exhaust pipe whichextends horizontally further toward the rear of the vehicle from anexhaust outlet on a right rear side of the DPF and opens toward the rearof the vehicle. The shortness of the exhaust pipe discharging the finalstage of the exhaust gas is a measure to prevent the vehicle body fromincreasing in length; however, when the exhaust pipe is insufficientlycooled, exhaust gas having a comparatively high temperature may bedischarged from the exhaust outlet. In the riding mower according toJapanese Patent Laid-open Publication No. 2012-026326, the radiator onlyextends to the height of the air filter, and cooling air that has passedthe radiator strikes the air filter or a front wall of the diesel engineand does not flow smoothly toward the rear of the engine compartment.

In a riding mower disclosed in Japanese Patent Laid-open Publication No.2013-209949, which has a similar format, in order to ensure an adequatelength for an exhaust pipe, exhaust gas exiting an exhaust gaspurification device flows through an exhaust passage, which extendsforward and upward from the exhaust gas purification device, after whichthe exhaust passage extends forward of and above the exhaust gaspurification device in a transverse direction of the vehicle until itpasses the diesel engine, and further extends along a side wall of thediesel engine so as to descend toward the front, after which the exhaustpassage reverses course and extends rearward along the side wall of thediesel engine to terminate at an exhaust outlet. With such an exhaustpipe layout, space above the rear portion of the engine and space besidea rear half of the engine is occupied by the exhaust pipe. Inparticular, a flow cross-sectional area of the exhaust pipe close to theexhaust outlet is large, and therefore the required space beside therear half of the engine is larger. As a result, a width of the hoodincreases. In the riding mower according to Japanese Patent Laid-openPublication No. 2013-209949, the radiator only extends to the height ofthe air filter, and cooling air that has passed the radiator strikes theair filter or a front wall of the diesel engine and does not flowsmoothly toward the rear of the engine compartment.

In view of the above, an appropriate arrangement of a radiator, aircleaner, and exhaust gas purification device is required in a mower inwhich a diesel engine is installed.

SUMMARY OF THE INVENTION

A mower according to the present invention includes: a vehicle frameextending in a front-back direction, the vehicle frame being suspendedon front wheels on a front side and on rear wheels on a rear side; amower unit mounted on the vehicle frame; a driver's seat provided to thevehicle frame; a transmission arranged below the driver's seat; a dieselengine arranged rearward of the transmission such that a bottom end ofthe engine is positioned higher than a bottom end of the transmission;an exhaust gas purification device arranged rearward of the dieselengine and provided with a filter collecting particulate mattercontained in exhaust gas discharged from the diesel engine; an aircleaner arranged forward of the exhaust gas purification device andabove the diesel engine; and a radiator extending from an area betweenthe transmission and the diesel engine so as to project further upwardthan the air cleaner through an area between the driver's seat and theair cleaner.

According to this configuration, the radiator is arranged to span fromthe area between the transmission and the diesel engine through the areabetween the driver's seat and the diesel engine, and to reach furtherupward. Moreover, cooling air that has entered from behind the driver'sseat and passed above the radiator passes through a vicinity of the aircleaner arranged above the diesel engine. The cooling air that haspassed below the radiator passes beside the diesel engine. The exhaustgas purification device is arranged rearward of the diesel engine;therefore, the exhaust gas purification device is not directly exposedto cooling airflow passing over the radiator. In addition, the radiatoris raised to a position high above the ground; therefore, a distancebetween the bottom ends of the transmission and diesel engine and thesurface of the ground can be increased effectively, a clearance angle toavoid contact between the rear portion of the vehicle and the groundwhen climbing a hill or clearing an obstacle is increased, andperformance of the mower is improved.

In another aspect of the present invention, the radiator is arrangedsuch that a height-direction center portion of the radiator ispositioned at the height of a top surface of a seat cushion of thedriver's seat. According to this configuration, airflow is generated inthe vicinity of the driver's back when sitting in the driver's seat andfresh air flows into the driver's vicinity. Therefore, a comfortablefeeling can be imparted to the driver.

The flow of air passing the radiator and entering the enginecompartment, on one hand, cools a surface of the engine while directlystriking the diesel engine, and also pushes hot air rising above thediesel engine away to lower a temperature within the engine compartment.In a case where the exhaust gas purification device is installed, hightemperatures may be generated while the filter, such as a DPF, is beingrenewed, and therefore the hot air in the vicinity of the exhaust gaspurification device must be pushed away. Therefore, in another aspect ofthe present invention, the radiator is arranged such that theheight-direction center portion of the radiator is at the same positionas a boundary region situated between the diesel engine and the aircleaner. Accordingly, cooling of the diesel engine itself, as well asoutflow of hot air above the engine and in the vicinity of the exhaustgas purification device, is achieved efficiently. In order toeffectively create an air flow passage achieving the cooling of thediesel engine itself, as well as the outflow of hot air above the engineand in the vicinity of the exhaust gas purification device, in anotheraspect of the present invention, a hood is provided covering theradiator, the diesel engine, the air cleaner, and the exhaust gaspurification device; and an air intake opening is formed on a front wallof the hood facing a cooling surface of the radiator. Thus, a coolingair passage is formed passing from a space between a seat back of thedriver's seat and the front wall, past a top half of the radiator, theair cleaner, and the exhaust gas purification device.

In the case of a mower, a great deal of debris such as grass clippingsis present in an area having a low height above the ground. Therefore,the cooling airflow is preferably guided in from as high an area aspossible. In addition, the driver's seat is attached at a positionslightly elevated by a seat attachment base provided to the vehicleframe. The seat attachment base therefore becomes an obstacle, making itdifficult to guide a large amount of air from an area below the driver'sseat. Due to configuration characteristics peculiar to such a mower, inorder to efficiently guide cooling airflow into the engine compartment,in another aspect of the present invention, a bottom end of the airintake opening on the front wall is positioned at a height position ofthe top surface of the seat cushion of the driver's seat.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed descriptionwhich follows, in reference to the noted plurality of drawings by way ofnon-limiting examples of exemplary embodiments of the present invention,in which like reference numerals represent similar parts throughout theseveral views of the drawings, and wherein:

FIG. 1 is a schematic side view illustrating a basic cooling structureof an engine compartment employed by a work vehicle according to thepresent invention;

FIG. 2 is a perspective view illustrating an arrangement of an exhaustgas purification device and an exhaust passage in a rear portion of anengine hood;

FIG. 3 is a side view of a zero turn mower according to an embodiment ofthe present invention;

FIG. 4 is a top or plan view of the zero-turn mower;

FIG. 5 is a side view of the engine compartment;

FIG. 6 is a top or plan view of the engine compartment;

FIG. 7 is an exploded perspective view of a rear frame, a radiator, andthe hood;

FIG. 8 is a front view of an area around the radiator;

FIG. 9 is a back view of an area around the exhaust gas purificationdevice; and

FIG. 10 is a perspective view of the area around the exhaust gaspurification device.

DETAILED DESCRIPTION OF THE INVENTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the embodiments of the present invention onlyand are presented in the cause of providing what is believed to be themost useful and readily understood description of the principles andconceptual aspects of the present invention. In this regard, no attemptis made to show structural details of the present invention in moredetail than is necessary for the fundamental understanding of thepresent invention, the description taken with the drawings makingapparent to those skilled in the art how the forms of the presentinvention may be embodied in practice.

Before describing a specific embodiment of a mower according to thepresent invention in which a diesel engine (hereafter referred to simplyas an engine) is mounted, a basic arrangement of a radiator 31, an aircleaner 32, and an exhaust gas purification device 36 in an enginecompartment covered by a hood 16 is described with reference to FIG. 1.The mower shown in FIG. 1 is rendered schematically, illustrating only avehicle frame 2 extending in a front-back direction of the vehicle, afront wheel unit 11, a rear wheel unit 12, a driver's seat 53 configuredby a seat cushion 53A and a seat-back 53B, a mower unit 6, atransmission 4, the diesel engine (hereafter referred to simply as theengine) 3, and engine peripheral components. The engine peripheralcomponents include the radiator 31, the air cleaner 32, a cooling fan33, and the exhaust gas purification device 36. Exhaust gas is expelledto a vehicle exterior through a discharge opening on an exhaust endportion 39. An exhaust manifold of the engine 3 and an inlet of theexhaust gas purification device 36 are connected by an inlet-sideexhaust passage 37, while an outlet of the exhaust gas purificationdevice 36 and the exhaust end portion 39 are connected by an outlet-sideexhaust passage 38. As a rule, in the present description, a front-backdirection refers to a longitudinal direction (travel direction) of themower; a lateral direction (left-right direction) refers to a widthdirection of the mower (i.e., a direction orthogonal to the front-backdirection); and a vertical direction refers to a direction perpendicularto the ground (horizontal plane).

The driver's seat 53 is arranged above a center region of the vehicleframe 2, and the transmission 4 is arranged below and rearward of thedriver's seat 53. A rear wheel axle of the rear wheel unit 12 extends ina transverse direction of the vehicle from a position rearward of thetransmission 4. The engine 3 is arranged rearward of the transmission 4,and at a position higher (height above the ground) than a bottom end ofthe transmission 4. Accordingly, on the vehicle frame 2, the heightabove the ground of a bottom end portion where the engine 3 is mountedis higher than the height above the ground of the bottom end portionwhere the transmission 4 is mounted. This increases an allowabledistance before the rear portion of the vehicle body contacts the groundwhen the front wheel unit 11 is raised, and improves an ability of thevehicle body to clear obstacles.

The exhaust gas purification device 36 is arranged rearward of theengine 3, at substantially the same height as the engine 3. The exhaustgas purification device 36 includes a substantially cylindrical housinghaving substantially the same length as the engine 3 in the transversedirection of the vehicle, and is fixated to the vehicle frame 2 suchthat a cylinder axis of the housing follows the transverse direction ofthe vehicle. The air cleaner 32, which similarly includes asubstantially cylindrical housing, is positioned above the engine 3 andat substantially a center position of the front-back direction length ofthe engine 3, such that the cylinder axis of the housing follows thetransverse direction of the vehicle.

The radiator 31 is oriented so as to be substantially upright and isarranged in an area between the transmission 4 and the engine 3. Abottom end of the radiator 31 is positioned directly above an inputshaft 30 that is coupled to a crank shaft so as to transmit drive forcefrom the engine 3 to the transmission 4, and a top end of the radiator31 projects further upward than the air cleaner 32. As shown in FIG. 1,in the lateral view of the mower, a height direction center portion ofthe radiator 31 is positioned at the height of a top surface of the seatcushion 53A of the driver's seat 53. The height direction center portionof the radiator 31 is substantially the same height as a boundary regionsituated between the engine 3 and the air cleaner 32.

The cooling fan 33, which has a rotation axis extending in thefront-back direction of the vehicle, is provided to an upper portion ofa front wall of the engine 3 and takes in outside air via a coolingsurface of the radiator 31. For purposes of clarity, FIG. 1 omits adepiction of a shroud provided between the radiator 31 and the coolingfan 33. An air intake opening 160 is formed on a front wall of the hood16, with the front wall facing the cooling surface of the radiator 31.The hood 16 covers the engine 3, the radiator 31, the air cleaner 32,and the exhaust gas purification device 36. A dust net is hung acrossthe air intake opening 160. A bottom end of the air intake opening 160is positioned at about a height position of the top surface of the seatcushion 53A of the driver's seat 53, i.e., at a height direction centerportion of the radiator 31. A space is formed between the seat back 53Bof the driver's seat 53 and the front wall of the hood 16 where air isable to circulate freely, and a cooling air pathway (shown by arrows inFIG. 1) is created that flows past the top half of the radiator 31, theair cleaner 32, and the exhaust gas purification device 36.

A line linking the top ends of the air cleaner 32 and the exhaust gaspurification device 36 descends toward the rear, and therefore a toppanel of the hood 16 is inclined in a similar shape. Cooling air runningpast the top half of the radiator 31 flows along the top panel of thehood 16 and obliquely downward, and is drawn downward in the area of therear wall of the hood 16. Accordingly, when an exhaust pipe, whichreleases exhaust gas exiting the exhaust gas purification device 36 tothe outside air, is exposed to the flow of cooling air, there is afavorable cooling effect.

Next, an exemplary layout of the exhaust pipe from the exhaust gaspurification device 36 is described with reference to FIG. 2. The outletof the exhaust gas purification device 36 and the exhaust end portion 39are connected. The outlet-side exhaust passage 38 is configured by afirst exhaust passage 381 and a second exhaust passage 382. The firstexhaust passage 381 is an exhaust circulation passage coupled to theoutlet of the exhaust gas purification device 36 and passing over theexhaust gas purification device 36 to reach beside a first end portionof the exhaust gas purification device 36 (in FIGS. 1 and 2, a rightside of the vehicle). The first exhaust passage 381 extends through aposition higher than a top end of the engine 3. The second exhaustpassage 382 is an exhaust circulation passage coupled to the firstexhaust passage 381 and extending in the transverse direction frombeside the first end portion of the exhaust gas purification device 36,below the exhaust gas purification device 36, to the exhaust end portion39.

A flow cross-sectional area of the second exhaust passage 382 is largerthan the flow cross-sectional area of the first exhaust passage 381, anda gap in the transverse direction is formed at the connection betweenthe first exhaust passage 381 and the second exhaust passage 382 suchthat outside air flows into the second exhaust passage 382 together withexhaust gas from the first exhaust passage 381. Moreover, the secondexhaust passage 382 is configured by a downward portion 3821 extendingdownward beside the first end portion of the exhaust gas purificationdevice 36; a sideways portion 3822 extending horizontally in a straightline below the exhaust gas purification device 36; and a two-dimensionalbend portion 3823 coupling the downward portion 3821 and the sidewaysportion 3822. In the example shown in FIG. 2, the downward portion 3821,the sideways portion 3822, and the two-dimensional bend portion 3823 areintegrally formed. The exhaust end portion 39, which is connectedsubstantially coaxially to a terminal end of the sideways portion 3822,is a cylindrical body. The discharge opening formed on the terminal endof the exhaust end portion 39 is oriented in the transverse direction ofthe vehicle.

The engine hood 16 which delineates the engine compartment is configuredby a front hood 16A covering the radiator 31, the cooling fan 33, andthe engine 3; and a rear hood 16B covering the exhaust gas purificationdevice 36 and the outlet-side exhaust passage 38. The rear hood 16Bserves as a downward deflection plate such that, after cooling air fromthe cooling fan 33 passes over the engine 3, the cooling air passesbehind the exhaust gas purification device 36 to arrive below theexhaust gas purification device 36.

Next, a specific embodiment of a riding mower according to the presentinvention is described with reference to the drawings. In the presentembodiment, a structure and arrangement are employed basically asdescribed with reference to FIGS. 1 and 2. FIGS. 3 and 4 show side andtop views of a mower known as a zero-turn mower and is one example of ariding mower. As illustrated in FIGS. 3 and 4, the mower is providedwith a traveling vehicle body 10 which is supported on the ground by thefront wheel unit, which includes the pair of left and right front wheels11, and by the rear wheel unit, which includes the pair of rotationallydriven left and right rear wheels 12. The traveling vehicle body 10includes the vehicle frame 2 as a base member, and the mower unit 6 issuspended from the vehicle frame 2 between the front wheels 11 and therear wheels 12 via a linking mechanism 14. An operation portion 5 isarranged in the center region of the traveling vehicle body 10 in thefront-back direction of the vehicle. Therefore, in the operation portion5, a seat support 52 is mounted on top of the vehicle frame 2 (seeFIG. 1) and the driver's seat 53 is provided to a top surface of theseat support 52. The driver's seat 53 is configured by the seat cushion53A, which holds or supports the driver's buttocks; and the seat back53B, which holds or supports the back of the driver. Further, fenders 17are formed on left and right side surfaces of the seat support 52.Finally, a step 50 is laid or located in front of the driver's seat 53.

A ROPS apparatus 13 is provided to the rear part of the operationportion 5. The engine 3 is arranged at the rear end region of thetraveling vehicle body 10 and the transmission 4 is arranged in front ofand slightly lower than the engine 3. The transmission 4 includes a leftrear-axle transmission portion 4 a and a right rear-axle transmissionportion 4 b. Although only the left rear-axle transmission portion 4 ais depicted in FIG. 3 using a dotted line, the right rear-axletransmission portion 4 b is arranged at a position axially symmetricwith the left rear-axle transmission portion 4 a on the right side ofthe vehicle. The left rear-axle transmission portion 4 a and the rightrear-axle transmission portion 4 b each have a built-in hydrostatictransmission (HST, an example of a continuously variable transmission),which may each be operated independently. The hydrostatic transmissioncan continuously vary the speed from low to high while the engine outputis in normal rotation. This includes forward or reverse rotation(backward) and the transmitting of the drive power of the engine to eachof the left and right rear wheels 12 a and 12 b of the rear wheel unit.Thereby, both the left and the right rear wheels 12 a and 12 b may bedriven in a forward direction at the same or substantially the samespeed to initiate straight line forward travel, and both the left andthe right rear wheels 12 a and 12 b may be driven in a backwarddirection at the same or substantially the same speed to initiatestraight line backwards travel. The traveling vehicle body 10 can bemade to turn in an arbitrary direction by ensuring the speeds of theleft and the right rear wheels 12 a and 12 b are different from eachother; for example, operating one of the left or right rear wheels 12 aor 12 b at a low speed near zero and operating the other of the rearwheels 12 a and 12 b forward or backward at a high speed can cause thetraveling vehicle body 10 to make a small turn. Additionally, drivingthe left and the right rear wheels 12 a and 12 b in mutually oppositedirections can cause the traveling vehicle body 10 to perform a spinningturn about a turning center that is substantially the center portionbetween the left and right rear wheels 12 a and 12 b. The front wheelunit is configured by a left-right pair of caster wheels, and can changeorientation freely about a vertical axis center. Thus, the front wheelunit is capable of correcting the orientation of the traveling vehiclein accordance with the travel direction, which is defined by how theleft and right rear wheels 12 are driven.

A speed change operation on the transmission 4, and in particular aspeed change operation on the left rear-axle transmission portion 4 aand the right rear-axle transmission portion 4 b, is carried out using apair of left and right speed change levers 51 arranged on both sides ofthe driver's seat 53. When the speed change levers 51 are held at afront-back direction neutral position, the continuously variabletransmission is in a neutral stop. When the speed change levers 51 aremoved forward or rearward from the neutral position, a forward speedchange or a backward speed change, respectively, occurs.

As shown in FIG. 4, the vehicle frame 2 of the traveling vehicle body 10is configured by a front frame 21 that is broad in width and a rearframe 22 that is narrow in width. The front frame 21 and the rear frame22 are configured by a left-right pair of vertical beams extending inthe front-back direction of the vehicle, and by a crossbeam linking thevertical beams. The width of the front frame 21 (space between the leftand right vertical beams) is greater than that of the rear frame 22, anda front portion of the rear frame 22 fits inside a rear portion of thefront frame 21 as seen in a plan view. The front portion of the rearframe 22 is coupled to the rear portion of the front frame 21 by acoupling member (not shown in the drawings). A box-shaped rear end frame220 is fixated to the rear end of the rear frame 22 so as to create aspace to the rear of the engine 3.

The engine 3 is installed in the middle of the rear frame 22 and isisolated from vibration. An input shaft 30 extends substantiallyhorizontally, coaxially with an extended portion of a crank shaftprotruding forward from a lower portion of the front wall of the engine3, the input shaft 30 transmitting drive power from the engine to thetransmission 4. In order to permit the greatest possible lifting of theleft and right front wheels 11 a and 11 b, the height of the rearportion of the traveling vehicle body 10 above the ground must beraised. Therefore, the engine 3 is arranged in a higher position off theground than the transmission 4. A PTO shaft 41 (see FIG. 1), whichtransmits drive power to the mower unit 6, projects forward from thefront wall of the transmission case 40 of the transmission 4. The heightof the transmission 4 above the ground is low so as to not increase anangle of inclination of a PTO intermediate shaft 62, which connects thePTO shaft 41 and the PTO input 61 of the mower unit 6.

The cooling fan 33 is arranged forward of the engine 3 such that a topend of the cooling fan 33 is at substantially the same height as the topend of the engine 3. The cooling fan 33 includes a rotation shaft 33 a(see FIG. 5) provided to a top portion of the front wall of the engine3, the rotation shaft 33 a extending in the front-back direction andtransmitting drive power from the extended portion of the crank shaftwith a belt transmission. The radiator 31 is arranged forward of thecooling fan 33. The radiator 31 is provided in an upright posture (i.e.,extending in a perpendicular direction) such that the cooling surface ofthe radiator 31 faces a rotation trajectory plane of the cooling fan 33.A bottom end of the radiator 31 is adjacent to the input shaft 30, andthe height of the bottom end is located at substantially a middle heightbetween the top end of the transmission 4 and the input shaft 30. Ashroud 330 is formed between the cooling fan 33 and the radiator 31. Asshown in FIGS. 6 and 7, left and right side portions of the shroud 330extend up to side panels of the hood 16 and act as a dividing wallseparating the engine compartment into an engine space and a radiatorspace.

As shown in FIG. 3, the hood 16 delineating the engine compartment isconfigured by a fixed hood 16B and a movable hood 16A, the fixed hood16B being the rear hood fixated to the rear end frame 220 and themovable hood 16A being the front hood opening and closing around anopen-close axis center Pb, which extends horizontally in the transversedirection of the vehicle. As shown in FIG. 7, the movable hood 16A isopen on a rear surface, and is configured by a left-right pair of sidepanels 161 forming side surfaces; a top panel 162 forming a top surface;and a front panel 163 forming a front surface. A plurality of openings165 are provided across the entire front panel 163, as well as on afront end region of the side panels 161 and the top panel 162. The dustnet is mounted to the openings 165. A rectangular recessed portion 164is formed on a lower half of the front side of the side panels 161, anda dust net-covered opening 165 is also provided to a side wall (sidesurface or top surface) of the recessed portion 164. Accordingly, asshown in FIG. 8, the cooling fan 33 can take in air through the topsurface and side surfaces of the movable hood 16A to create a coolingairflow.

The front panel 163 of the movable hood 16A is bent in a lateraldirection crease. When the movable hood 16A is in a closed state, thelower half of the front panel 163 forms a perpendicular surface, whereasthe upper half of the front panel 163 forms an inclined surfaceinclining toward the rear. As clearly shown in FIG. 5, an airflow spaceis formed between the front panel 163 of the closed movable hood 16A andthe occupied seat back 53B, and essentially, a horizontalcross-sectional area of the airflow space progressively increasesfurther upward. By driving the cooling fan 33, the cooling airflow takenin through the airflow space passes over the radiator 31 and flows intothe area around the engine 3. The cooling airflow strikes the front walland flows into a space above the engine 3.

A dust cover 311 is also mounted to the front surface of the radiator31. A material that is finer than the dust cover is arranged to cover tothe openings 165 is used as the mesh of the dust cover 311. The dustcover 311 is bent such that a top end thereof acts as a handle 3111. Thedust cover 311 is mounted to the radiator 31 so as to be capable ofbeing pulled upward. Accordingly, when the dust cover 311 is to beremoved, a hand reaches in from above, grips the handle 3111, and pullsthe dust cover 311 upward. The handle 3111 is not bent at a 90° angle,but rather is bent at a somewhat gentler angle, such as 70°, tofacilitate gripping.

The cylindrical air cleaner 32 lies horizontally (such that a cylinderaxis lies along the transverse direction of the vehicle) above theengine 3. An inflow pipe 331 of the air cleaner 32 extends upward at aslight angle from the air cleaner 32 and runs through a top portion ofthe shroud 330. An intake opening 320 of the inflow pipe 331 reaches atop end of the radiator 31 in the radiator space. An outflow pipe 332 ofthe air cleaner 32 extends downward, bending in a “U” shape, andconnects to an intake manifold of the engine 3. The height of the bottomend of the radiator 31 is substantially the height of the crank shaft,and the height of the top end of the radiator 31 is substantially theheight of the intake opening 320 of the air cleaner 32. In other words,the radiator 31 extends so as to project upward through a region betweenthe driver's seat 53 and the air cleaner 32, higher than the top end ofthe air cleaner 32.

As shown in FIGS. 5 and 6, the exhaust gas purification device 36, whichhas substantially a cylindrical shape, is arranged to the rear of theengine 3 and lying horizontally (such that the cylinder axis lies alongthe transverse direction of the vehicle) and substantially at the heightof the engine 3. A filter called a DPF is installed in the exhaust gaspurification device 36, with the DPF collecting particulate mattercontained in the exhaust gas discharged from the engine 3. The exhaustgas purification device 36 is interposed in the exhaust pipe system ofthe engine 3. The exhaust pipe system is configured by the exhaust endportion 39 forming a discharge opening 390 expelling exhaust gas to thevehicle exterior; with the inlet-side exhaust passage 37 connecting theexhaust manifold of the engine 3 and an inlet 361 of the exhaust gaspurification device 36; and the outlet-side exhaust passage 38connecting an outlet 362 of the exhaust gas purification device 36 andthe exhaust end portion 39.

As clearly shown in FIGS. 9 and 10, the outlet-side exhaust passage 38is configured by the first exhaust passage 381 and the second exhaustpassage 382. A projecting end of the first exhaust passage 381 iscoupled to the outlet 362 of the exhaust gas purification device 36. Thefirst exhaust passage 381 rises from the outlet 362 at a forward angleabove the exhaust gas purification device 36, then bends into a U-turnshape, a terminal end of which extends to be beside the right-side endof the exhaust gas purification device 36. A projecting end of thesecond exhaust passage 382 is coupled to the first exhaust passage 381.In the present embodiment, the coupling of the first exhaust passage 381to the second exhaust passage 382 is a coupled state where the terminalend of the first exhaust passage 381, which is formed to have a diametergreater than the first exhaust passage 381, is either inserted into theprojecting end of the second exhaust passage 382, or is positionedsubstantially coplanar with or spaced slightly apart from the projectingend of the second exhaust passage 382, thereby creating a gap betweenthe two members through which the cooling airflow enters. The secondexhaust passage 382 is configured by the downward portion 3821, whichhas substantially a straight line shape and runs beside the right-sideend portion of the exhaust gas purification device 36; the sidewaysportion 3822 extending in the transverse direction of the vehicle belowthe exhaust gas purification device 36 to reach the exhaust end portion39; and the 90° bend portion 3823 coupling the downward portion 3821 andthe sideways portion 3822. The bend portion 3823 is formed as atwo-dimensional bent path, the center axis of which is positioned on atwo-dimensional plane. The coupling of the second exhaust passage 382 tothe exhaust end portion 39 is also a coupled state where the terminalend of the second exhaust passage 382 is either inserted into theexhaust end portion 39, which is formed to have a diameter greater thanthe second exhaust passage 382, or is positioned substantially coplanarwith or spaced slightly apart from the exhaust end portion 39, therebycreating a gap between the two members through which the cooling airflowenters.

As clearly shown in FIG. 5, a sectional face of the interior surface ofthe fixed hood 16B, as seen in a side view, has a shape that follows arearward, side view outline of the exhaust gas purification device 36,the first exhaust passage 381, and the second exhaust passage 382. Inother words, the interior surface of the fixed hood 16B acts as adownward deflection plate oriented such that the cooling air that haspassed through or around the air cleaner 32 moves from the first exhaustpassage 381 behind the exhaust gas purification device 36 to arrivebelow the exhaust gas purification device 36. In the present embodiment,a first deflection plate 160 a causing the cooling air to flow downwardand rearward is provided to the interior of the top portion of the fixedhood 16B, and a second deflection plate 160 b causing the cooling air toflow downward and forward is provided to the interior of the bottomportion of the fixed hood 16B.

As shown in FIGS. 3 and 7, the ROPS 13 includes a left-right pair ofsupporting columns 13 a and a horizontal member 13 b connecting thesupporting columns 13 a. The supporting columns 13 a can pivot to bendin the middle. A leg 131, which is the lower half of the supportingcolumn 13 a, curves inward at substantially the same height position asthe top end of the rear frame 22, and extends until reaching the rearend of the front frame 21. The rear end of the front frame 21 and theleg 131 of the ROPS 13 are coupled via a coupling bracket. Astraight-line support column 132, which is the upper half of the supportcolumn 13 a, is coupled to the leg 131 via a pivoting coupler so as tobe capable of pivoting between a vertical posture and a sideways (ordownward) posture.

The step 50 is mounted to the front frame 21 in a foot area of thedriver's seat 53. The fenders 17 are provided on the left and right ofthe driver's seat 53, and fuel tanks 18 are provided below each of thefenders 17. A brake pedal 191 is arranged close to the center of a frontregion of the step 50. A brake lock pedal 192 for parking, which holdsthe brake pedal 191 in a depressed position, is provided beside thebrake pedal 191.

Other Embodiments

(1) In the specific embodiment described above, a zero-turn mower isexemplified as the mower. However, the present invention can also beutilized on a different mower such as a front mower, in which the mowerunit 6 is mounted forward of the front wheels 11.

(2) In the specific embodiment described above, the hood 16 was dividedinto a front hood (the movable hood 16A) and a rear hood (the fixed hood16B). Instead, both sections may be movable hoods, or the hood 16 may beconfigured as an undivided, single member.

(3) In the specific embodiment described above, the first deflectionplate 160 a and the second deflection plate 160 b were formed on theinterior of the top portion of the fixed hood 16B. However, thedeflection plates may be formed as components of the fixed hood 16B, oras separate components. In addition, instead of two deflection plates, aconfiguration may be employed which creates an effect deflecting coolingair with a single component, or with three or more components.

The present invention can be applied to a work vehicle having a dieselengine installed in a rear portion of a vehicle frame.

It is noted that the foregoing examples have been provided merely forthe purpose of explanation and are in no way to be construed as limitingof the present invention. While the present invention has been describedwith reference to exemplary embodiments, it is understood that the wordswhich have been used herein are words of description and illustration,rather than words of limitation. Changes may be made, within the purviewof the appended claims, as presently stated and as amended, withoutdeparting from the scope and spirit of the present invention in itsaspects. Although the present invention has been described herein withreference to particular structures, materials and embodiments, thepresent invention is not intended to be limited to the particularsdisclosed herein; rather, the present invention extends to allfunctionally equivalent structures, methods and uses, such as are withinthe scope of the appended claims.

The present invention is not limited to the above described embodiments,and various variations and modifications may be possible withoutdeparting from the scope of the present invention.

What is claimed is:
 1. A mower comprising: a vehicle frame extending ina front-back direction and being suspended on front wheels and rearwheels; a mower unit mounted on or to the vehicle frame; a driver's seatarranged on the vehicle frame; a transmission arranged at leastpartially below the driver's seat; a diesel engine located behind thetransmission such that a bottom of the engine is positioned higher thana bottom of the transmission; an exhaust gas purification devicearranged on a location behind the diesel engine and being configured tocollect particulate matter contained in exhaust gas discharged from thediesel engine; an air cleaner arranged at a location in front of theexhaust gas purification device and above the diesel engine; and aradiator located in an area between the transmission and the dieselengine and having an upper end disposed at a higher position than theair cleaner.
 2. The mower according to claim 1, wherein the radiator hasa lower end disposed below an upper end of the transmission.
 3. Themower according to claim 1, wherein the upper end of the radiator isarranged adjacent each of: an air inlet arranged on a hood; and an airintake inlet coupled to the air cleaner.
 4. The mower according to claim1, wherein the radiator is arranged between the driver's seat and theair cleaner.
 5. The mower according to claim 1, wherein the exhaust gaspurification device comprises a filter collecting particulate matter. 6.The mower according to claim 1, wherein a vertical center of theradiator is arranged at substantially a same height as a top surface ofa seat cushion of the driver's seat.
 7. The mower according to claim 1,wherein a vertical center of the radiator is arranged at substantially asame height as a region arranged above the diesel engine and below theair cleaner.
 8. The mower according to claim 1, further comprising ahood configured to cover the radiator, the diesel engine, the aircleaner, and the exhaust gas purification device.
 9. The mower accordingto claim 8, wherein the hood comprises an air intake opening located ona front wall of the hood facing a cooling surface of the radiator. 10.The mower according to claim 8, wherein the hood is spaced from thedriver's seat so as to define an air space from which cooling air can bedrawn into the hood and through a top half of the radiator so as toproviding cooling air for cooling that passes around the air cleaner andthe exhaust gas purification device.
 11. The mower according to claim 1,further comprising a hood having a front wall and an air opening locatedat a position above a top surface of a seat cushion of the driver'sseat.
 12. A mower comprising: a vehicle frame extending in a front-backdirection and being suspended on front wheels and rear wheels; a mowerunit mounted on or to the vehicle frame; a driver's seat arranged on thevehicle frame; a transmission; a diesel engine located behind thetransmission such that a bottom of the engine is positioned higher thana bottom of the transmission; an exhaust gas purification devicearranged on a location behind the diesel engine and being configured tocollect particulate matter contained in exhaust gas discharged from thediesel engine; an air cleaner arranged at a location in front of theexhaust gas purification device and above the diesel engine; a radiatorlocated in front of the diesel engine; one or more air inlets configuredto allow external air to enter into the air cleaner; and one or more airinlets configured to allow external air to pass through an upper portionof the radiator.
 13. The mower according to claim 12, wherein theradiator has a lower end disposed below an upper end of thetransmission.
 14. The mower according to claim 12, wherein an upper endof the radiator is arranged adjacent each of: an upper wall of a hood;and a front inclined wall of the hood.
 15. A mower comprising: a vehicleframe extending in a front-back direction and being suspended on frontwheels and rear wheels; a mower unit mounted on or to the vehicle frame;a driver's seat arranged on the vehicle frame; a transmission; a dieselengine located behind the transmission such that a bottom of the engineis positioned higher than a bottom of the transmission; an exhaust gaspurification device arranged on a location behind the diesel engine andbeing configured to collect particulate matter contained in exhaust gasdischarged from the diesel engine; an air cleaner arranged at a locationin front of the exhaust gas purification device and above the dieselengine; a radiator located in from of the diesel engine; and a hoodhaving one or more air inlets arranged on a generally upper surface andone or more air inlets arranged on a generally forward facing surface.16. The mower according to claim 15, wherein an upper end of theradiator is arranged adjacent the one or more air inlets arranged on thegenerally upper surface.
 17. The mower according to claim 15, whereinthe generally upper surface decreases in height toward a rear end of themower.
 18. The mower according to claim 15, wherein the generallyforward facing surface faces largely forward and slightly upward. 19.The mower according to claim 15, wherein air entering the hood via theone or more air inlets arranged on the forward facing surface can passthrough an upper portion of the radiator to provide cooling air aroundto the exhaust gas purification device.
 20. The mower according to claim15, wherein air entering the hood via the one or more air inletsarranged on the upper surface can pass into an air intake, said airintake being coupled to the air cleaner and being located behind anupper end of the radiator.